Check Up: Alcohol: How great a risk?

Posted: November 14, 2011

A glass of red wine can warm the heart on a chilly fall evening, and some data show it will also improve your cardiovascular health.

But women who take one sip may no longer deserve to wear that pink ribbon. Even moderate drinkers are encouraging the enemy - breast cancer - at least according to the latest news from the Journal of the American Medical Association.

A recent study shows that even one drink a day can raise a woman's risk by 15 percent. The findings come from a large study that followed 105,986 nurses over 28 years.

It's easy to turn that into a scare story, and some journalists may be tempted to do this so they can get out of work in time for happy hour. But the reality is more complicated. It shows how medical studies can be misinterpreted.

First, many people reading this will conclude that if your risk without drinking is 12 percent, then drinking will push it up by an additional 15 percent to 27 percent. This is wrong. Your new risk would be 13.8 percent.

Beyond that, the average risk is not the same as the risk if you abstain. Average risk folds in everyone - including women with high-risk genetic mutations and those who spend each night in bars pounding cosmopolitans.

Therefore, it might make more sense to say that if you drink an average amount, you still face an average risk, while teetotalers would have a reduced risk.

In an editorial for the journal, Steven Narod of the Women's College Research Institute in Toronto put it in terms of a 10-year risk for getting breast cancer; it would go from 2.8 percent for nondrinkers to 3.5 percent for those having one drink a day and 4.1 percent for those taking two or more drinks a day.

To complicate things further, the study can't specify whether the risk comes from drinking earlier or later in life. So Narod finds "there is no data to provide assurance that giving up alcohol will reduce breast cancer risk."

That's because the damage might already be done from decades of past drinking. There really aren't any data on women who used to drink and then quit.

Finally, drinking is a trade-off, Narod wrote. Giving up alcohol means forgoing the possible benefits of an occasional glass of red wine for heart health. Now that alone could drive a woman to drink.